Toner manufacturing processes often employ various surfactants, ions and other additives, for example, to facilitate reaction steps, impart a desired property on an intermediate, to enhance reaction yield and so on. For example, ions can be introduced into an EA process to control particle size and shape, including providing stability of the toner particles during aggregation and coalescence.
Toner triboelectric charge, toner flowability and other properties contribute to use of same and to producing images of quality. Such properties depend, in part, on the surface characteristics of a toner, which can, for example, contribute or shape toner surface charge and charge capacity.
Thus, it can be beneficial to have nonessential entities at the toner particle surface, such as, surfactants and ions, removed from the final toner. For example, surfactant may cause toner to lose charge. Also, surfactant can impact environmental resistance. Hence, surface surfactants and ions may have a negative influence on the toner at high temperature and/or humidity, for example, preventing. stable development and adequate transfer of toner. In addition, pollution on the surface of the toner may lead to decrease in toner flowability and/or preservation properties, resulting in decreases in toner properties and product consistency.
Ionic Liquids (ILs) are organic salts which can have melting points below, for example, 100° C. While ordinary liquids, such as, water and gasoline, are predominantly made of electrically neutral molecules, ILs are largely made of ions and short-lived ion pairs. ILs also are known as liquid electrolytes, ionic melts, ionic fluids, fused salts, liquid salts or ionic glasses. In general, ILs combine a unique set of properties, including, but not limited to, non-volatility, non-flammability, electrical conductivity and highly selective solubility. Some IL's have a low negative impact on the environment, being, for example, relatively non-toxic and/or readily degraded. Such distinctive properties make ILs attractive alternatives in fields such as, organic chemistry, electrochemistry, catalysis, physical chemistry and engineering.
Washing protocols using water have been used to remove pollutants from toner surfaces (see, e.g., U.S. Pat. No. 7,439,004). Such protocols require high amounts of water, multiple washing steps and long cycle times. However, that can only remove surfactants/ions from the water phase and superficial particle surfaces, leaving behind bound pollutants or those beneath or within the superficial layers, which pollutants can have a critical impact on toner performance.
It is desirable, therefore, to integrate an aid into a toner manufacturing process to control the surfactants, ions and so on, which can have a negative on the environment, on toner particle surfaces and at the same time to have a lower negative impact on the environment, such as, lower water usage when producing EA toners. The unique properties of ILs, which can be readily degraded, provide a versatile, effective, economical and safe toner washing protocol.